- Title
- The use of a silica based coating to reduce moisture absorption of flax fibre reinforced composites
- Creator
- Bala, Sandisiwe
- Subject
- Chromatographic analysis
- Subject
- Nonwoven fabrics Nanocomposites (Materials)
- Date Issued
- 2018
- Date
- 2018
- Type
- Thesis
- Type
- Masters
- Type
- MSc
- Identifier
- http://hdl.handle.net/10948/23349
- Identifier
- vital:30534
- Description
- This study deals with the synthesis of silica particles, treatment of flax fabrics with silica, and the preparation and characterization of silica coated flax fibre reinforced phenolic composites treated with silica. Silica particles were successfully prepared by means of a hydrolytic sol-gel route. Two types of silica were prepared by employing either ammonium hydroxide solution as a base catalyst and acetic acid as an acid catalyst. The silica sols were then aged from three to five days in order to determine the effects of aging on the final properties of the silica. The chemical composition of the silica particles was evaluated by fourier transform infrared spectroscopy (FTIR), thermal stability was determined by using thermogravimetric analysis (TGA), and structural and physical properties of the silica particles prepared via two catalysts and aged at different time periods was investigated by x-ray diffraction (XRD). Silica sols, prepared at different conditions were then applied to treat flax fabrics (untreated/scoured) by use of the padding technique. The effects of the silica treatments on flax fabrics were evaluated by FTIR, XRD, determination of moisture content and mechanical properties. The FTIR revealed presence of silica groups on the silica treated flax fabrics, thus resulting in low moisture content for silica treated flax fabrics. XRD analysis revealed that aging the silica sols increases the crystallinity index. Silica treated flax fabrics showed enhanced tensile properties in the weft direction. The thermal, mechanical and water sorption properties of the composites were evaluated. TGA results revealed that the decomposition temperatures of the silica treated composites shifted to higher temperatures. Thus, silica treatments lead to an improvement in thermal stability for composites. A reduction in mechanical properties was also observed for silica treated composites and some composites showed a reduction in water absorption. It was quite evident from this study that the type of catalyst system used in silica preparation has a great influence on the final properties of the silica, which to a large extent changes the thermal, mechanical and water sorption properties of the composites.
- Format
- xii, 143 leaves
- Format
- Publisher
- Nelson Mandela University
- Publisher
- Faculty of Science
- Language
- English
- Rights
- Nelson Mandela University
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